Charitable donations will not show up on their 1099-B tax statement. Since they gave away shares with gains instead of selling them, this action will not be reported to the IRS and is not a taxable event.
If your clients itemize their deductions to take charitable deductions, they (or their tax software or accountant) will report the donation when they file their taxes. Their donation receipts, available in their account in the Documents section of the Activity tab, will be useful in this process. Donation receipts are kept for their and your records and are not filed with their taxes.
For non-cash charitable contributions (including share donations from Betterment) over $500, your clients must fill in a Form-8283 when they file their taxes.
If they’re using TurboTax or another tax filing software, it will typically ask them about their donation details and fill out the Form-8283 for them.
This information is not meant to be tax advice.